For use with Lectrosonics and Comtek brand audio transmitters only. FreqFinder calculates the intermodulation products of user entered transmitter channels and then suggests options of channels that will be compatible with user transmitters already in use. Recommended for use with 12-24 transmitter systems depending on the processing power of your device and the spread of your transmitters. US Customers: FCC TV database functionality available now as a preview (will be a $15 in-app purchase in the future). Accesses the FCC database for local TV broadcast towers and estimates the field strength at your location for better channel selection. The preview will expire in February.